E-Tech electric boat motors, used and distributed by Maine Cat

8 Feb

 

When I wrote enthusiastically about the then-new Maine Cat MC 38 in 2016, my only reservation was the gasoline outboards (though MC has used them on other sailing cat models for years). But then again, the lightweight, low drag 38 design seemed perfect for ever-improving electric propulsion and twin drives should give it reliable and excellent maneuverability around docks.

So I’ve followed closely as builder/designer Dick Vermeulen pursued an electric solution, and while that’s been a somewhat bumpy road, there are now two interesting stories in progress:  Maine Cat recently became the E-Tech distributor for North America and several MC 38 LS-E sailing cats will launch this spring with E-Tech outboards, hydro generation included.

E-Tech 4 Pod Outboard and Torqeedo Cruise 4.0 RL on Maine Cat test boat

E-Tech electric drives come in every configuration I’m aware of — shaft drive, fixed pod, steerable pod, or outboard — as well as multiple sizes between 2 and 40 kW. And Vermeulen, who visited the E-Tech factory near Warsaw after a METS test drive last fall, is purportedly ready to supply systems for new builds or refits, even customized if needed.

Meanwhile, the E-Tech on the Maine Cat test boat above is the specific 4 Pod Outboard model that now comes standard on the MC 38 LS-E, and it’s quite a contrast to the Torqeedo Cruise 4.0 RL that was the original plan. While power and cost are similar — the 4 Pod 4.3 kW retails for $4,830, the Cruise 4 kW for $4,500 — a lot else is different. I view them as a lightweight electric outboard design scaled up versus an electric pod drive made over as an outboard.

E-Tech outboard with CMC power lift as set up for Maine Cat MC 38

So while the manual lift Cruise 4 only weighs 38 pounds, each 4 Pod with long shaft and CMC power lift going on the new Maine Cat 38 totals nearly 100 pounds. And though the beefy rig (similar to above) seems well suited to a 6-ton, 38-foot performance cruising catamaran — especially as they’ll hinge down from under the main deck, a neat MC design they’ve used before –it might be awkward and/or ugly on a smaller boat’s transom.

Also,  E-Tech uses 3-phase AC synchronous motors versus Torqeedo’s digitally controlled DC motors, and maybe that accounts for the 20% improved efficiency that Dick says he’s seeing with the outboard testing? But I think it also accounts for the controller water cooling required with E-Tech models over 10kW, which sounds like wasted energy (though Dick suggests it could be used to heat a boat’s water tank).

And while Torqeedo outboards can helpfully calculate real-time range based on battery state, kW in use, and speed (from built-in GPS), E-Tech outboards are the first I know of with hydro generation. That feature may be irrelevant for most electric outboard installs, but it could be highly valued on the MC 38. Dick estimates that the two E-Tech 4 Pods can generate 1 kW when sailing at 9 knots, which is over 80 amps in terms of familiar 12v boat use.

But hydro generation is not completely free. That MC38 will go even faster with the E-Techs lifted clear of the water, and maximum sailing performance is one reason that Dick stayed with the outboard configuration instead of fixed pods (which would also be harder to service).

(Incidentally, Torqeedo outboards apparently cannot be made to hydro generate and, in fact, I see no reference to it even with the Pod Drives and Sail Drives where that feature is common. Then again it’s certainly included with the Deep Blue 25kW SD model; heck, Moon Wave’s skipper told me it worked great all the way across the Atlantic last spring. This is confusing and I will try to resolve.)

In conclusion, E-Tech looks like a good choice for some uses, especially the MC 38, and I look forward to seeing how the combination performs on the water this spring.

Maine Cat MC 38 LS-E propulsion and power 48v system diagram

Maine Cat MC 38 LS-E propulsion and power 48v system diagram

PS It’s telling that the main battery and power system for the electric drive MC 38 remained the same despite the change in motor brands. That’s because 48v DC is rapidly becoming the sweet spot not just for mid-size e-boats, but also modern on-engine-generator/storage solutions like Integrel (and some off-grid photovoltaic systems).

As I understand it, 50v DC triggers more difficult design standards and so 48 is the “low voltage” choice that’s most efficient for moving larger DC loads around. Note here that battery bank, motors, solar array, inverter/charger and genset are all on the 48v bus while 48-to-24/12 DC-DC converters handle the smaller and more conventional boat loads. And judging from the MC 38 LS-E design details, many of the 48v components will be off-the-shelf Victron, which can even auto start the Whisper Power Piccolo 5 Genverter.

If I were completely redoing Gizmo’s core power system, I would be looking hard at jumping from 12v DC to 48.

This article was syndicated from Panbo

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